This invention relates to a method and apparatus for measuring trap densities and distribution in dielectric films.
The properties of dielectric films such as SiO.sub.2 and Si.sub.3 N.sub.4 used in integrated circuit devices, have an important bearing upon the ultimate performance and life expectancy of such devices. Their properties depend upon the nature and density of traps (i.e., defects in the film) unavoidably produced by various processing methods and by subsequent environmental stresses such as radiation. A trap is an energy state which may accept either or both polarities of charge (i.e., electrons or holes) depending on its exact nature. A simple and direct method for measuring trap density and distribution is useful in evaluating the quality and reliability of such films, and hence is useful in determining preferred processing techniques and limitations on device application (e.g. radiation exposure).